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gen_smtp_client.erl
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gen_smtp_client.erl
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%%% Copyright 2009 Andrew Thompson <[email protected]>. All rights reserved.
%%%
%%% Redistribution and use in source and binary forms, with or without
%%% modification, are permitted provided that the following conditions are met:
%%%
%%% 1. Redistributions of source code must retain the above copyright notice,
%%% this list of conditions and the following disclaimer.
%%% 2. Redistributions in binary form must reproduce the above copyright
%%% notice, this list of conditions and the following disclaimer in the
%%% documentation and/or other materials provided with the distribution.
%%%
%%% THIS SOFTWARE IS PROVIDED BY THE FREEBSD PROJECT ``AS IS'' AND ANY EXPRESS OR
%%% IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
%%% MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
%%% EVENT SHALL THE FREEBSD PROJECT OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
%%% INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
%%% (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
%%% LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
%%% ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
%%% (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
%%% SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
%% @doc A simple SMTP client used for sending mail - assumes relaying via a
%% smarthost.
-module(gen_smtp_client).
-define(DEFAULT_OPTIONS, [
% whether to connect on 465 in ssl mode
{ssl, false},
% always, never, if_available
{tls, if_available},
% used in ssl:connect, http://erlang.org/doc/man/ssl.html
{tls_options, [{versions, ['tlsv1', 'tlsv1.1', 'tlsv1.2']}]},
{auth, if_available},
{hostname, smtp_util:guess_FQDN()},
% how many retries per smtp host on temporary failure
{retries, 1},
{on_transaction_error, quit}
]).
-define(AUTH_PREFERENCE, [
"CRAM-MD5",
"LOGIN",
"PLAIN",
"XOAUTH2"
]).
-define(TIMEOUT, 1200000).
-ifdef(TEST).
-include_lib("eunit/include/eunit.hrl").
-compile([export_all, nowarn_export_all]).
-else.
-export([send/2, send/3, send_blocking/2, open/1, deliver/2, close/1]).
-endif.
-export_type([
smtp_client_socket/0,
email/0,
email_address/0,
options/0,
callback/0,
smtp_session_error/0,
host_failure/0,
failure/0,
validate_options_error/0
]).
-type email_address() :: string() | binary().
-type email() :: {
From :: email_address(),
To :: [email_address(), ...],
Body :: string() | binary() | fun(() -> string() | binary())
}.
-type options() :: [
{ssl, boolean()}
| {tls, always | never | if_available}
% ssl:option() / ssl:tls_client_option()
| {tls_options, list()}
| {sockopts, [gen_tcp:connect_option()]}
| {port, inet:port_number()}
| {timeout, timeout()}
| {relay, inet:ip_address() | inet:hostname()}
| {no_mx_lookups, boolean()}
| {auth, always | never | if_available}
| {hostname, string()}
| {retries, non_neg_integer()}
| {username, string()}
| {password, string()}
| {trace_fun, fun((Fmt :: string(), Args :: [any()]) -> any())}
| {on_transaction_error, quit | reset}
].
-type extensions() :: [{binary(), binary()}].
-record(smtp_client_socket, {
socket :: smtp_socket:socket(),
host :: string(),
extensions :: list(),
options :: list()
}).
-opaque smtp_client_socket() :: #smtp_client_socket{}.
-type callback() :: fun(
(
{exit, any()}
| smtp_session_error()
| {ok, binary()}
) -> any()
).
%% Smth that is thrown from inner SMTP functions
% server's 5xx response
-type permanent_failure_reason() ::
binary()
| auth_failed
| ssl_not_started.
%server's 4xx response
-type temporary_failure_reason() ::
binary()
| tls_failed.
-type validate_options_error() ::
no_relay
| invalid_port
| no_credentials.
-type failure() ::
{temporary_failure, temporary_failure_reason()}
| {permanent_failure, permanent_failure_reason()}
| {missing_requirement, auth | tls}
| {unexpected_response, [binary()]}
| {network_failure, {error, timeout | inet:posix()}}.
-type smtp_host() :: inet:hostname().
-type host_failure() ::
{temporary_failure, smtp_host(), temporary_failure_reason()}
| {permanent_failure, smtp_host(), permanent_failure_reason()}
| {missing_requirement, smtp_host(), auth | tls}
| {unexpected_response, smtp_host(), [binary()]}
| {network_failure, smtp_host(), {error, timeout | inet:posix()}}.
-type smtp_session_error() ::
{error, no_more_hosts | send, {permanent_failure, smtp_host(), permanent_failure_reason()}}
| {error, retries_exceeded | send, host_failure()}.
-spec send(Email :: email(), Options :: options()) ->
{'ok', pid()} | {'error', validate_options_error()}.
%% @doc Send an email in a non-blocking fashion via a spawned_linked process.
%% The process will exit abnormally on a send failure.
send(Email, Options) ->
send(Email, Options, undefined).
%% @doc Send an email nonblocking and invoke a callback with the result of the send.
%% The callback will receive either `{ok, Receipt}' where Receipt is the SMTP server's receipt
%% identifier, `{error, Type, Message}' or `{exit, ExitReason}', as the single argument.
-spec send(Email :: email(), Options :: options(), Callback :: callback() | 'undefined') ->
{'ok', pid()} | {'error', validate_options_error()}.
send(Email, Options, Callback) ->
NewOptions = lists:ukeymerge(
1,
lists:sort(Options),
lists:sort(?DEFAULT_OPTIONS)
),
case check_options(NewOptions) of
ok ->
Pid = spawn_link(
fun() ->
try send_it(Email, NewOptions) of
{error, _Type, _Reason} = Error when is_function(Callback, 1) ->
Callback(Error);
{error, _Type, _Reason} = Error ->
exit(Error);
Receipt when is_function(Callback, 1) ->
Callback({ok, Receipt});
_Receipt ->
ok
catch
exit:Reason when is_function(Callback, 1) ->
Callback({exit, Reason})
end
end
),
{ok, Pid};
{error, Reason} ->
{error, Reason}
end.
-spec send_blocking(Email :: email(), Options :: options()) ->
binary()
| smtp_session_error()
| {error, validate_options_error()}.
%% @doc Send an email and block waiting for the reply. Returns either a binary that contains
%% the SMTP server's receipt or `{error, Type, Message}' or `{error, Reason}'.
send_blocking(Email, Options) ->
NewOptions = lists:ukeymerge(
1,
lists:sort(Options),
lists:sort(?DEFAULT_OPTIONS)
),
case check_options(NewOptions) of
ok ->
send_it(Email, NewOptions);
{error, Reason} ->
{error, Reason}
end.
-spec open(Options :: options()) ->
{ok, SocketDescriptor :: smtp_client_socket()}
| smtp_session_error()
| {error, bad_option, validate_options_error()}.
%% @doc Open a SMTP client socket with the provided options
%% Once the socket has been opened, you can use it with deliver/2.
open(Options) ->
NewOptions = lists:ukeymerge(
1,
lists:sort(Options),
lists:sort(?DEFAULT_OPTIONS)
),
case check_options(NewOptions) of
ok ->
RelayDomain = proplists:get_value(relay, NewOptions),
MXRecords =
case proplists:get_value(no_mx_lookups, NewOptions) of
true ->
[];
_ ->
smtp_util:mxlookup(RelayDomain)
end,
trace(Options, "MX records for ~s are ~p~n", [RelayDomain, MXRecords]),
Hosts =
case MXRecords of
[] ->
% maybe we're supposed to relay to a host directly
[{0, RelayDomain}];
_ ->
MXRecords
end,
try_smtp_sessions(Hosts, NewOptions, []);
{error, Reason} ->
{error, bad_option, Reason}
end.
-spec deliver(Socket :: smtp_client_socket(), Email :: email()) ->
{'ok', Receipt :: binary()} | {error, FailMsg :: failure()}.
%% @doc Deliver an email on an open smtp client socket.
%% For use with a socket opened with open/1. The socket can be reused as long as the previous call to deliver/2 returned `{ok, Receipt}'.
%% If the previous call to deliver/2 returned `{error, FailMsg}' and the option `{on_transaction_error, reset}' was given in the open/1 call,
%% the socket <em>may</em> still be reused.
deliver(#smtp_client_socket{} = SmtpClientSocket, Email) ->
#smtp_client_socket{
socket = Socket,
extensions = Extensions,
options = Options
} = SmtpClientSocket,
try
Receipt = try_sending_it(Email, Socket, Extensions, Options),
{ok, Receipt}
catch
throw:FailMsg ->
{error, FailMsg}
end.
-spec close(Socket :: smtp_client_socket()) -> ok.
%% @doc Close an open smtp client socket opened with open/1.
close(#smtp_client_socket{socket = Socket}) ->
quit(Socket).
-spec send_it(Email :: email(), Options :: options()) ->
binary()
| smtp_session_error().
send_it(Email, Options) ->
RelayDomain = to_string(proplists:get_value(relay, Options)),
MXRecords =
case proplists:get_value(no_mx_lookups, Options) of
true ->
[];
_ ->
smtp_util:mxlookup(RelayDomain)
end,
trace(Options, "MX records for ~s are ~p~n", [RelayDomain, MXRecords]),
Hosts =
case MXRecords of
[] ->
% maybe we're supposed to relay to a host directly
[{0, RelayDomain}];
_ ->
MXRecords
end,
case try_smtp_sessions(Hosts, Options, []) of
{error, _, _} = Error ->
Error;
{ok, ClientSocket} ->
#smtp_client_socket{
socket = Socket,
host = Host,
extensions = Extensions,
options = Options1
} = ClientSocket,
try
try_sending_it(Email, Socket, Extensions, Options1)
catch
throw:{FailureType, Message} ->
{error, send, {FailureType, Host, Message}}
after
quit(Socket)
end
end.
-spec try_smtp_sessions(
Hosts :: [{non_neg_integer(), string()}, ...], Options :: options(), RetryList :: list()
) ->
{ok, smtp_client_socket()}
| smtp_session_error().
try_smtp_sessions([{_Distance, Host} | _Tail] = Hosts, Options, RetryList) ->
try
{ok, open_smtp_session(Host, Options)}
catch
throw:FailMsg ->
handle_smtp_throw(FailMsg, Hosts, Options, RetryList)
end.
-spec handle_smtp_throw(failure(), [{non_neg_integer(), smtp_host()}], options(), list()) ->
{ok, smtp_client_socket()}
| smtp_session_error().
handle_smtp_throw({permanent_failure, Message}, [{_Distance, Host} | _Tail], _Options, _RetryList) ->
% permanent failure means no retries, and don't even continue with other hosts
{error, no_more_hosts, {permanent_failure, Host, Message}};
handle_smtp_throw(
{temporary_failure, tls_failed}, [{_Distance, Host} | _Tail] = Hosts, Options, RetryList
) ->
% Could not start the TLS handshake; if tls is optional then try without TLS
case proplists:get_value(tls, Options) of
if_available ->
NoTLSOptions = [{tls, never} | proplists:delete(tls, Options)],
try open_smtp_session(Host, NoTLSOptions) of
Res -> {ok, Res}
catch
throw:FailMsg ->
handle_smtp_throw(FailMsg, Hosts, Options, RetryList)
end;
_ ->
try_next_host({temporary_failure, tls_failed}, Hosts, Options, RetryList)
end;
handle_smtp_throw(FailMsg, Hosts, Options, RetryList) ->
try_next_host(FailMsg, Hosts, Options, RetryList).
try_next_host({FailureType, Message}, [{_Distance, Host} | _Tail] = Hosts, Options, RetryList) ->
Retries = proplists:get_value(retries, Options),
RetryCount = proplists:get_value(Host, RetryList),
case fetch_next_host(Retries, RetryCount, Hosts, RetryList, Options) of
{[], _NewRetryList} ->
{error, retries_exceeded, {FailureType, Host, Message}};
{NewHosts, NewRetryList} ->
try_smtp_sessions(NewHosts, Options, NewRetryList)
end.
fetch_next_host(Retries, RetryCount, [{_Distance, Host} | Tail], RetryList, Options) when
is_integer(RetryCount), RetryCount >= Retries
->
% out of chances
trace(Options, "retries for ~s exceeded (~p of ~p)~n", [Host, RetryCount, Retries]),
{Tail, lists:keydelete(Host, 1, RetryList)};
fetch_next_host(Retries, RetryCount, [{Distance, Host} | Tail], RetryList, Options) when
is_integer(RetryCount)
->
trace(Options, "scheduling ~s for retry (~p of ~p)~n", [Host, RetryCount, Retries]),
{Tail ++ [{Distance, Host}], lists:keydelete(Host, 1, RetryList) ++ [{Host, RetryCount + 1}]};
fetch_next_host(0, _RetryCount, [{_Distance, Host} | Tail], RetryList, _Options) ->
% done retrying completely
{Tail, lists:keydelete(Host, 1, RetryList)};
fetch_next_host(Retries, _RetryCount, [{Distance, Host} | Tail], RetryList, Options) ->
% otherwise...
trace(Options, "scheduling ~s for retry (~p of ~p)~n", [Host, 1, Retries]),
{Tail ++ [{Distance, Host}], lists:keydelete(Host, 1, RetryList) ++ [{Host, 1}]}.
-spec open_smtp_session(Host :: string(), Options :: options()) -> smtp_client_socket().
open_smtp_session(Host, Options) ->
{ok, Socket, _Host2, Banner} = connect(Host, Options),
trace(Options, "connected to ~s; banner was ~s~n", [Host, Banner]),
{ok, Extensions} = try_EHLO(Socket, Options),
trace(Options, "Extensions are ~p~n", [Extensions]),
{Socket2, Extensions2} = try_STARTTLS(Socket, Options, Extensions),
trace(Options, "Extensions are ~p~n", [Extensions2]),
Authed = try_AUTH(Socket2, Options, proplists:get_value(<<"AUTH">>, Extensions2)),
trace(Options, "Authentication status is ~p~n", [Authed]),
#smtp_client_socket{
socket = Socket2,
host = Host,
extensions = Extensions,
options = Options
}.
-spec try_sending_it(
Email :: email(),
Socket :: smtp_socket:socket(),
Extensions :: extensions(),
Options :: options()
) -> binary().
try_sending_it({From, To, Body}, Socket, Extensions, Options) ->
try_MAIL_FROM(From, Socket, Extensions, Options),
try_RCPT_TO(To, Socket, Extensions, Options),
try_DATA(Body, Socket, Extensions, Options).
-spec try_MAIL_FROM(
From :: email_address(),
Socket :: smtp_socket:socket(),
Extensions :: extensions(),
Options :: options()
) -> true.
try_MAIL_FROM(From, Socket, Extensions, Options) when is_binary(From) ->
try_MAIL_FROM(binary_to_list(From), Socket, Extensions, Options);
try_MAIL_FROM("<" ++ _ = From, Socket, _Extensions, Options) ->
OnTxError = proplists:get_value(on_transaction_error, Options),
% TODO do we need to bother with SIZE?
smtp_socket:send(Socket, ["MAIL FROM:", From, "\r\n"]),
case read_possible_multiline_reply(Socket) of
{ok, <<"250", _Rest/binary>>} ->
true;
{ok, <<"4", _Rest/binary>> = Msg} when OnTxError =:= reset ->
rset_or_quit(Socket),
throw({temporary_failure, Msg});
{ok, <<"4", _Rest/binary>> = Msg} ->
quit(Socket),
throw({temporary_failure, Msg});
{ok, <<"5", _Rest/binary>> = Msg} when OnTxError =:= reset ->
trace(Options, "Mail FROM rejected: ~p~n", [Msg]),
ok = rset_or_quit(Socket),
throw({permanent_failure, Msg});
{ok, Msg} ->
trace(Options, "Mail FROM rejected: ~p~n", [Msg]),
quit(Socket),
throw({permanent_failure, Msg})
end;
try_MAIL_FROM(From, Socket, Extension, Options) ->
% someone was bad and didn't put in the angle brackets
try_MAIL_FROM("<" ++ From ++ ">", Socket, Extension, Options).
-spec try_RCPT_TO(
Tos :: [email_address()],
Socket :: smtp_socket:socket(),
Extensions :: extensions(),
Options :: options()
) -> true.
try_RCPT_TO([], _Socket, _Extensions, _Options) ->
true;
try_RCPT_TO([To | Tail], Socket, Extensions, Options) when is_binary(To) ->
try_RCPT_TO([binary_to_list(To) | Tail], Socket, Extensions, Options);
try_RCPT_TO(["<" ++ _ = To | Tail], Socket, Extensions, Options) ->
OnTxError = proplists:get_value(on_transaction_error, Options),
smtp_socket:send(Socket, ["RCPT TO:", To, "\r\n"]),
case read_possible_multiline_reply(Socket) of
{ok, <<"250", _Rest/binary>>} ->
try_RCPT_TO(Tail, Socket, Extensions, Options);
{ok, <<"251", _Rest/binary>>} ->
try_RCPT_TO(Tail, Socket, Extensions, Options);
{ok, <<"4", _Rest/binary>> = Msg} when OnTxError =:= reset ->
rset_or_quit(Socket),
throw({temporary_failure, Msg});
{ok, <<"4", _Rest/binary>> = Msg} ->
quit(Socket),
throw({temporary_failure, Msg});
{ok, <<"5", _Rest/binary>> = Msg} when OnTxError =:= reset ->
rset_or_quit(Socket),
throw({permanent_failure, Msg});
{ok, Msg} ->
quit(Socket),
throw({permanent_failure, Msg})
end;
try_RCPT_TO([To | Tail], Socket, Extensions, Options) ->
% someone was bad and didn't put in the angle brackets
try_RCPT_TO(["<" ++ To ++ ">" | Tail], Socket, Extensions, Options).
-spec try_DATA(
Body :: binary() | function(),
Socket :: smtp_socket:socket(),
Extensions :: extensions(),
Options :: options()
) -> binary().
try_DATA(Body, Socket, Extensions, Options) when is_function(Body) ->
try_DATA(Body(), Socket, Extensions, Options);
try_DATA(Body, Socket, _Extensions, Options) ->
OnTxError = proplists:get_value(on_transaction_error, Options),
smtp_socket:send(Socket, "DATA\r\n"),
case read_possible_multiline_reply(Socket) of
{ok, <<"354", _Rest/binary>>} ->
%% Escape period at start of line (rfc5321 4.5.2)
EscapedBody = re:replace(Body, <<"^\\\.">>, <<"..">>, [
global, multiline, {return, binary}
]),
smtp_socket:send(Socket, [EscapedBody, "\r\n.\r\n"]),
case read_possible_multiline_reply(Socket) of
{ok, <<"250 ", Receipt/binary>>} ->
Receipt;
{ok, <<"4", _Rest2/binary>> = Msg} when OnTxError =:= reset ->
throw({temporary_failure, Msg});
{ok, <<"4", _Rest2/binary>> = Msg} ->
quit(Socket),
throw({temporary_failure, Msg});
{ok, <<"5", _Rest2/binary>> = Msg} when OnTxError =:= reset ->
throw({permanent_failure, Msg});
{ok, Msg} ->
quit(Socket),
throw({permanent_failure, Msg})
end;
{ok, <<"4", _Rest/binary>> = Msg} when OnTxError =:= reset ->
rset_or_quit(Socket),
throw({temporary_failure, Msg});
{ok, <<"4", _Rest/binary>> = Msg} ->
quit(Socket),
throw({temporary_failure, Msg});
{ok, <<"5", _Rest/binary>> = Msg} when OnTxError =:= reset ->
rset_or_quit(Socket),
throw({permanent_failure, Msg});
{ok, Msg} ->
quit(Socket),
throw({permanent_failure, Msg})
end.
-spec try_AUTH(Socket :: smtp_socket:socket(), Options :: options(), AuthTypes :: [string()]) ->
boolean().
try_AUTH(Socket, Options, []) ->
case proplists:get_value(auth, Options) of
always ->
quit(Socket),
erlang:throw({missing_requirement, auth});
_ ->
false
end;
try_AUTH(Socket, Options, undefined) ->
case proplists:get_value(auth, Options) of
always ->
quit(Socket),
erlang:throw({missing_requirement, auth});
_ ->
false
end;
try_AUTH(Socket, Options, AuthTypes) ->
case
proplists:is_defined(username, Options) and
proplists:is_defined(password, Options) and
(proplists:get_value(auth, Options) =/= never)
of
false ->
case proplists:get_value(auth, Options) of
always ->
quit(Socket),
erlang:throw({missing_requirement, auth});
_ ->
false
end;
true ->
Username = to_binary(proplists:get_value(username, Options)),
Password = to_binary(proplists:get_value(password, Options)),
trace(Options, "Auth types: ~p~n", [AuthTypes]),
Types = re:split(AuthTypes, " ", [{return, list}, trim]),
case do_AUTH(Socket, Username, Password, Types, Options) of
false ->
case proplists:get_value(auth, Options) of
always ->
quit(Socket),
erlang:throw({permanent_failure, auth_failed});
_ ->
false
end;
true ->
true
end
end.
to_string(String) when is_list(String) -> String;
to_string(Binary) when is_binary(Binary) -> binary_to_list(Binary).
to_binary(String) when is_binary(String) -> String;
to_binary(String) when is_list(String) -> list_to_binary(String).
-spec do_AUTH(
Socket :: smtp_socket:socket(),
Username :: binary(),
Password :: binary(),
Types :: [string()],
Options :: options()
) -> boolean().
do_AUTH(Socket, Username, Password, Types, Options) ->
FixedTypes = [string:to_upper(X) || X <- Types],
trace(Options, "Fixed types: ~p~n", [FixedTypes]),
AllowedTypes = [X || X <- ?AUTH_PREFERENCE, lists:member(X, FixedTypes)],
trace(Options, "available authentication types, in order of preference: ~p~n", [AllowedTypes]),
do_AUTH_each(Socket, Username, Password, AllowedTypes, Options).
-spec do_AUTH_each(
Socket :: smtp_socket:socket(),
Username :: binary(),
Password :: binary(),
AuthTypes :: [string()],
Options :: options()
) -> boolean().
do_AUTH_each(_Socket, _Username, _Password, [], _Options) ->
false;
do_AUTH_each(Socket, Username, Password, ["CRAM-MD5" | Tail], Options) ->
smtp_socket:send(Socket, "AUTH CRAM-MD5\r\n"),
case read_possible_multiline_reply(Socket) of
{ok, <<"334 ", Rest/binary>>} ->
Seed64 = binstr:strip(binstr:strip(Rest, right, $\n), right, $\r),
Seed = base64:decode(Seed64),
Digest = smtp_util:compute_cram_digest(Password, Seed),
String = base64:encode(list_to_binary([Username, " ", Digest])),
smtp_socket:send(Socket, [String, "\r\n"]),
case read_possible_multiline_reply(Socket) of
{ok, <<"235", _Rest/binary>>} ->
trace(Options, "authentication accepted~n", []),
true;
{ok, Msg} ->
trace(Options, "authentication rejected: ~s~n", [Msg]),
do_AUTH_each(Socket, Username, Password, Tail, Options)
end;
{ok, Something} ->
trace(Options, "got ~s~n", [Something]),
do_AUTH_each(Socket, Username, Password, Tail, Options)
end;
do_AUTH_each(Socket, Username, Password, ["XOAUTH2" | Tail], Options) ->
Str = base64:encode(list_to_binary(["user=", Username, 1, "auth=Bearer ", Password, 1, 1])),
smtp_socket:send(Socket, ["AUTH XOAUTH2 ", Str, "\r\n"]),
case read_possible_multiline_reply(Socket) of
{ok, <<"235", _Rest/binary>>} ->
true;
{ok, _Msg} ->
do_AUTH_each(Socket, Username, Password, Tail, Options)
end;
do_AUTH_each(Socket, Username, Password, ["LOGIN" | Tail], Options) ->
smtp_socket:send(Socket, "AUTH LOGIN\r\n"),
{ok, Prompt} = read_possible_multiline_reply(Socket),
case is_auth_username_prompt(Prompt) of
true ->
%% base64 Username: or username:
trace(Options, "username prompt~n", []),
U = base64:encode(Username),
smtp_socket:send(Socket, [U, "\r\n"]),
{ok, Prompt2} = read_possible_multiline_reply(Socket),
case is_auth_password_prompt(Prompt2) of
true ->
%% base64 Password: or password:
trace(Options, "password prompt~n", []),
P = base64:encode(Password),
smtp_socket:send(Socket, [P, "\r\n"]),
case read_possible_multiline_reply(Socket) of
{ok, <<"235 ", _Rest/binary>>} ->
trace(Options, "authentication accepted~n", []),
true;
{ok, Msg} ->
trace(Options, "password rejected: ~s", [Msg]),
do_AUTH_each(Socket, Username, Password, Tail, Options)
end;
false ->
trace(Options, "username rejected: ~s", [Prompt2]),
do_AUTH_each(Socket, Username, Password, Tail, Options)
end;
false ->
trace(Options, "got ~s~n", [Prompt]),
do_AUTH_each(Socket, Username, Password, Tail, Options)
end;
do_AUTH_each(Socket, Username, Password, ["PLAIN" | Tail], Options) ->
AuthString = base64:encode(<<0, Username/binary, 0, Password/binary>>),
smtp_socket:send(Socket, ["AUTH PLAIN ", AuthString, "\r\n"]),
case read_possible_multiline_reply(Socket) of
{ok, <<"235", _Rest/binary>>} ->
trace(Options, "authentication accepted~n", []),
true;
Else ->
% TODO do we need to bother trying the multi-step PLAIN?
trace(Options, "authentication rejected ~p~n", [Else]),
do_AUTH_each(Socket, Username, Password, Tail, Options)
end;
do_AUTH_each(Socket, Username, Password, [Type | Tail], Options) ->
trace(Options, "unsupported AUTH type ~s~n", [Type]),
do_AUTH_each(Socket, Username, Password, Tail, Options).
is_auth_username_prompt(<<"334 VXNlcm5hbWU6\r\n">>) -> true;
is_auth_username_prompt(<<"334 dXNlcm5hbWU6\r\n">>) -> true;
is_auth_username_prompt(<<"334 VXNlcm5hbWU6 ", _/binary>>) -> true;
is_auth_username_prompt(<<"334 dXNlcm5hbWU6 ", _/binary>>) -> true;
is_auth_username_prompt(_) -> false.
is_auth_password_prompt(<<"334 UGFzc3dvcmQ6\r\n">>) -> true;
is_auth_password_prompt(<<"334 cGFzc3dvcmQ6\r\n">>) -> true;
is_auth_password_prompt(<<"334 UGFzc3dvcmQ6 ", _/binary>>) -> true;
is_auth_password_prompt(<<"334 cGFzc3dvcmQ6 ", _/binary>>) -> true;
is_auth_password_prompt(_) -> false.
-spec try_EHLO(Socket :: smtp_socket:socket(), Options :: options()) -> {ok, extensions()}.
try_EHLO(Socket, Options) ->
ok = smtp_socket:send(Socket, [
"EHLO ", proplists:get_value(hostname, Options, smtp_util:guess_FQDN()), "\r\n"
]),
case read_possible_multiline_reply(Socket) of
{ok, <<"500", _Rest/binary>>} ->
% Unrecognized command, fall back to HELO
try_HELO(Socket, Options);
{ok, <<"4", _Rest/binary>> = Msg} ->
quit(Socket),
throw({temporary_failure, Msg});
{ok, Reply} ->
{ok, parse_extensions(Reply, Options)}
end.
-spec try_HELO(Socket :: smtp_socket:socket(), Options :: options()) -> {ok, list()}.
try_HELO(Socket, Options) ->
ok = smtp_socket:send(Socket, [
"HELO ", proplists:get_value(hostname, Options, smtp_util:guess_FQDN()), "\r\n"
]),
case read_possible_multiline_reply(Socket) of
{ok, <<"250", _Rest/binary>>} ->
{ok, []};
{ok, <<"4", _Rest/binary>> = Msg} ->
quit(Socket),
throw({temporary_failure, Msg});
{ok, Msg} ->
quit(Socket),
throw({permanent_failure, Msg})
end.
% check if we should try to do TLS
-spec try_STARTTLS(
Socket :: smtp_socket:socket(), Options :: options(), Extensions :: extensions()
) -> {smtp_socket:socket(), extensions()}.
try_STARTTLS(Socket, Options, Extensions) ->
case {proplists:get_value(tls, Options), proplists:get_value(<<"STARTTLS">>, Extensions)} of
{Atom, true} when Atom =:= always; Atom =:= if_available ->
trace(Options, "Starting TLS~n", []),
case {do_STARTTLS(Socket, Options), Atom} of
{false, always} ->
trace(Options, "TLS failed~n", []),
quit(Socket),
erlang:throw({temporary_failure, tls_failed});
{false, if_available} ->
trace(Options, "TLS failed~n", []),
{Socket, Extensions};
{{S, E}, _} ->
trace(Options, "TLS started~n", []),
{S, E}
end;
{always, _} ->
quit(Socket),
erlang:throw({missing_requirement, tls});
_ ->
trace(Options, "TLS not requested ~p~n", [Options]),
{Socket, Extensions}
end.
%% attempt to upgrade socket to TLS
-spec do_STARTTLS(Socket :: smtp_socket:socket(), Options :: options()) ->
{smtp_socket:socket(), extensions()} | false.
do_STARTTLS(Socket, Options) ->
smtp_socket:send(Socket, "STARTTLS\r\n"),
case read_possible_multiline_reply(Socket) of
{ok, <<"220", _Rest/binary>>} ->
case
catch smtp_socket:to_ssl_client(
Socket, [binary | proplists:get_value(tls_options, Options, [])], 5000
)
of
{ok, NewSocket} ->
%NewSocket;
{ok, Extensions} = try_EHLO(NewSocket, Options),
{NewSocket, Extensions};
{'EXIT', Reason} ->
quit(Socket),
error_logger:error_msg("Error in ssl upgrade: ~p.~n", [Reason]),
erlang:throw({temporary_failure, tls_failed});
{error, closed} ->
quit(Socket),
error_logger:error_msg("Error in ssl upgrade: socket closed.~n"),
erlang:throw({temporary_failure, tls_failed});
{error, ssl_not_started} ->
quit(Socket),
error_logger:error_msg("SSL not started.~n"),
erlang:throw({permanent_failure, ssl_not_started});
Else ->
trace(Options, "~p~n", [Else]),
false
end;
{ok, <<"4", _Rest/binary>> = Msg} ->
quit(Socket),
erlang:throw({temporary_failure, Msg});
{ok, Msg} ->
quit(Socket),
erlang:throw({permanent_failure, Msg})
end.
%% try connecting to a host
connect(Host, Options) when is_binary(Host) ->
connect(binary_to_list(Host), Options);
connect(Host, Options) ->
AddSockOpts =
case proplists:get_value(sockopts, Options) of
undefined -> [];
Other -> Other
end,
SockOpts = [binary, {packet, line}, {keepalive, true}, {active, false} | AddSockOpts],
Proto =
case proplists:get_value(ssl, Options) of
true ->
ssl;
_ ->
tcp
end,
Port =
case proplists:get_value(port, Options) of
undefined when Proto =:= ssl ->
465;
OPort when is_integer(OPort) ->
OPort;
_ ->
25
end,
Timeout =
case proplists:get_value(timeout, Options) of
undefined -> 5000;
OTimeout -> OTimeout
end,
case smtp_socket:connect(Proto, Host, Port, SockOpts, Timeout) of
{ok, Socket} ->
case read_possible_multiline_reply(Socket) of
{ok, <<"220", Banner/binary>>} ->
{ok, Socket, Host, Banner};
{ok, <<"4", _Rest/binary>> = Msg} ->
quit(Socket),
throw({temporary_failure, Msg});
{ok, Msg} ->
quit(Socket),
throw({permanent_failure, Msg})
end;
{error, Reason} ->
throw({network_failure, {error, Reason}})
end.
%% read a multiline reply (eg. EHLO reply)
-spec read_possible_multiline_reply(Socket :: smtp_socket:socket()) -> {ok, binary()}.
read_possible_multiline_reply(Socket) ->
case smtp_socket:recv(Socket, 0, ?TIMEOUT) of
{ok, Packet} ->
case binstr:substr(Packet, 4, 1) of
<<"-">> ->
Code = binstr:substr(Packet, 1, 3),
read_multiline_reply(Socket, Code, [Packet]);
<<" ">> ->
{ok, Packet}
end;
Error ->
throw({network_failure, Error})
end.
-spec read_multiline_reply(Socket :: smtp_socket:socket(), Code :: binary(), Acc :: [binary()]) ->
{ok, binary()}.
read_multiline_reply(Socket, Code, Acc) ->
case smtp_socket:recv(Socket, 0, ?TIMEOUT) of
{ok, Packet} ->
case {binstr:substr(Packet, 1, 3), binstr:substr(Packet, 4, 1)} of
{Code, <<" ">>} ->
{ok, list_to_binary(lists:reverse([Packet | Acc]))};
{Code, <<"-">>} ->
read_multiline_reply(Socket, Code, [Packet | Acc]);
_ ->
quit(Socket),
throw({unexpected_response, lists:reverse([Packet | Acc])})
end;
Error ->
throw({network_failure, Error})
end.
rset_or_quit(Socket) ->
ok = smtp_socket:send(Socket, "RSET\r\n"),
case read_possible_multiline_reply(Socket) of
{ok, <<"250", _Rest/binary>>} ->
ok;
{ok, _Msg} ->
quit(Socket)
end.
quit(Socket) ->
smtp_socket:send(Socket, "QUIT\r\n"),
smtp_socket:close(Socket),
ok.
% TODO - more checking
check_options(Options) ->
CheckedOptions = [relay, port, auth],
lists:foldl(
fun(Option, State) ->
case State of
ok ->
Value = proplists:get_value(Option, Options),
check_option({Option, Value}, Options);
Other ->
Other
end
end,
ok,
CheckedOptions
).
check_option({relay, undefined}, _Options) ->
{error, no_relay};
check_option({relay, _}, _Options) ->
ok;
check_option({port, undefined}, _Options) ->
ok;
check_option({port, Port}, _Options) when is_integer(Port) -> ok;
check_option({port, _}, _Options) ->
{error, invalid_port};
check_option({auth, always}, Options) ->
case
proplists:is_defined(username, Options) and
proplists:is_defined(password, Options)
of
false ->
{error, no_credentials};
true ->
ok
end;
check_option({auth, _}, _Options) ->
ok.
-spec parse_extensions(Reply :: binary(), Options :: options()) -> extensions().
parse_extensions(Reply, Options) ->
[_ | Reply2] = re:split(Reply, "\r\n", [{return, binary}, trim]),
[
begin
Body = binstr:substr(Entry, 5),
case re:split(Body, " ", [{return, binary}, trim, {parts, 2}]) of
[Verb, Parameters] ->
{binstr:to_upper(Verb), Parameters};
[Body] ->
case binstr:strchr(Body, $=) of
0 ->
{binstr:to_upper(Body), true};
_ ->
trace(Options, "discarding option ~p~n", [Body]),
[]
end
end
end
|| Entry <- Reply2
].
trace(Options, Format, Args) ->
case proplists:get_value(trace_fun, Options) of
undefined -> ok;
F -> F(Format, Args)
end.
-ifdef(TEST).
session_start_test_() ->
{foreach, local,
fun() ->
{ok, ListenSock} = smtp_socket:listen(tcp, 9876),
{ListenSock}
end,
fun({ListenSock}) ->
smtp_socket:close(ListenSock)
end,
[
fun({ListenSock}) ->
{"simple session initiation", fun() ->
Options = [{relay, "localhost"}, {port, 9876}, {hostname, "testing"}],
{ok, _Pid} = send({"[email protected]", ["[email protected]"], "hello world"}, Options),
{ok, X} = smtp_socket:accept(ListenSock, 1000),
smtp_socket:send(X, "220 Some banner\r\n"),
?assertMatch({ok, "EHLO testing\r\n"}, smtp_socket:recv(X, 0, 1000)),
ok
end}
end,
fun({ListenSock}) ->
{"retry on crashed EHLO twice if requested", fun() ->
Options = [
{relay, "localhost"}, {port, 9876}, {hostname, "testing"}, {retries, 2}
],
{ok, _Pid} = send({"[email protected]", ["[email protected]"], "hello world"}, Options),
{ok, X} = smtp_socket:accept(ListenSock, 1000),
smtp_socket:send(X, "220 Some banner\r\n"),
?assertMatch({ok, "EHLO testing\r\n"}, smtp_socket:recv(X, 0, 1000)),
smtp_socket:close(X),
{ok, Y} = smtp_socket:accept(ListenSock, 1000),
smtp_socket:send(Y, "220 Some banner\r\n"),
?assertMatch({ok, "EHLO testing\r\n"}, smtp_socket:recv(Y, 0, 1000)),
smtp_socket:close(Y),
{ok, Z} = smtp_socket:accept(ListenSock, 1000),
smtp_socket:send(Z, "220 Some banner\r\n"),
?assertMatch({ok, "EHLO testing\r\n"}, smtp_socket:recv(Z, 0, 1000)),
ok
end}
end,
fun({ListenSock}) ->
{"retry on crashed EHLO", fun() ->
Options = [{relay, "localhost"}, {port, 9876}, {hostname, "testing"}],
{ok, Pid} = send({"[email protected]", ["[email protected]"], "hello world"}, Options),
unlink(Pid),
Monitor = erlang:monitor(process, Pid),
{ok, X} = smtp_socket:accept(ListenSock, 1000),
smtp_socket:send(X, "220 Some banner\r\n"),